Thanks, everyone. You guys are correct about the money and variety. However, I'd like a 35 that's the same profile as my 34s. To make me sound even weirder, I'm very fond of my newer AT2s. They are prefect in heavy duty rocks and great on the road. I don't do much mud, but they should suffice. I do a bunch of mountain snow, and the reports that I've heard leave me confident that they'll get me up and down this winter. With a 50,000-mile tread warranty, they should last a while, or much more than the MTs.
So, 285x75x17s are 33.9"x11.3". 285x75x18s are 34.8"x11.3". Both are E-rated, which I like. There is no sacrifice in sidewall height/flex between the 17s and 18s, as there are when you go to an 18 with a shorter sidewall. I like to keep my tires inside the fenders as much as possible, and I lean toward a little thinner tire, so I'm not crazy about 12.50 17s. Where the limited variety hurts is in quality rims. I'd like an 18x8.5 with around 5-5.25 backspace, but it looks like18x9 is about all there is. I found 1-2 ProComp and American Racing wheels, but don't know the quality. A Raceline rim may be better if I can find one.